Two groups of drugs which are heavily used by the elderly have been subjected to molecular manipulations in order to learn how their pharmacological profiles may be improved. In the group of adrenergic blockers it has been established that attachment of drugs to a polysaccharide carrier by a stable bond sustains their activity. Such hydrolysis-stable conjugates do not penetrate cell membranes, a process which conditions many side-effects. Furthermore the conjugates have increased specific recognition compared to the parent drug. In the group of lipid soluble vitamins, the formation of a physical complex between the carrier which has been synthesized and vitamin A leads to sustenance of biological activities with some decrease in its toxic effects.